Various kinds of winding machines are known for winding printed products up so as to form a roll and maintaining them in the wound arrangement by means of a holding element. Such holding elements are typically bands, string, foils and the like. In order to be able to roll up the printed products in a roll or tubular form and simultaneously or in a subsequent operating step apply the holding element, it is necessary to have guidance or pressing devices which initiate and aid the winding process. U.S. Pat. No. 4,909,015 discloses an apparatus of this general type which makes it possible to use holding elements with limited rigidity. A plastic foil or film is unwound from a delivery roll and is applied under tensile stress to an advancing flow of imbricated printed products. The film and a section of the printed products are supplied by either separate of a common supply means to a winding station where they are wound together around a winding mandrel. At the end of the winding process, the film is cut off at a desired point. Winding is accomplished by the freely rotatable winding mandrel and is driven by an endless belt which drives the mandrel with the printed products and which also exerts certain radial pressure on the printed products.
At the start of the winding process, when the endless belt engages the periphery of the winding mandrel or the wound printed products to a significant extent, relatively good contact pressure is obtained. However, the more the printed products are wound, the less favorable is the sector covered by the belt. Near the end of the winding process, the periphery of the roll is engaged by the belt only over the a sector of 180.degree.. This can have a disadvantageous influence on the winding process, particularly during the final winding phase. The desired strength of the roll suffers and controlled pressing of the printed products and the holding element holding them together can no longer be assured. A further disadvantage of this and other known apparatus is the time taken and the mechanically rather complicated ejection process for a finished printed product roll.
The aforementioned disadvantages and problems become even more serious if it is necessary to wind the more recently known compact rolls, such as is shown in U.S. Pat. No. 5,101,610 in which rolls are formed from a densely compressed scale flow. The radially outwardly-acting forces which then occur, as well as the starting of the winding process, including the deflecting or reversing of the scale flow during winding, can only inadequately be dealt with using conventional devices.